Free float steam trap

ABSTRACT

This invention relates to a free float steam trap which comprises a trap casing having an inlet port and an outlet port and a valve chest formed therein, a valve seat member attached to the lower portion of the valve chest and having a valve orifice opened through which the valve chest communicates with the outlet port, a float valve arranged in a free state in the valve chest, rising and descending in accordance with the water level in the valve chest to directly open and close the valve orifice and a means for dispersing and passing condensate flow downward, provided at a fluid inlet through which the inlet port communicates with valve chest.

FIELD OF THE INVENTION

The present invention relates to a free float steam trap adapted todirectly open and close a valve orifice by a float valve accommodated ina free state in a valve chest, thereby automatically discharging onlycondensate from the mixture of steam and the condensate, based on abasic concept that difference in specific gravity between the steam andthe condensate is employed.

BACKGROUND OF THE INVENTION

For example, a free float steam trap disclosed in Japanese unexaminedpatent publication No. 55-135292 is provided with a spherical floatitself which rises due to buoyancy and descends in a free state in avalve chest and also has a function of valve body. The steam trap ofthis type is provided with a single operating portion in comparison witha conventional steam trap in which a float, a level and a valve body areindividually separate, and its structure is extremely simple, so thatthere occurs little trouble. Furthermore, since the entire surface ofits float valve put in a free state forms a seal surface, a new valvesurface can be easily obtained relative to a valve seat.

The construction of the conventional free float steam trap is shown inFIG. 7. A trap casing is constituted by attaching a cover member 93 to amain body 90 having an inlet port 91 and an outlet port 92. A valvechest 94 is formed in the interior portion thereof. A float valve 95 isaccommodated in a free state in the valve chest 94. A valve seat member96 is mounted on a lower portion of the valve chest 94 and held by aplug 97. At the valve seat member 96 is formed a valve orifice 98 openedto the valve chest 94. The valve orifice 98 communicates with the outletport 92 through an outlet passage 99. Condensate entering from the inletport 91 stays in the valve chest 94. The float valve 95 rises anddescends due to buoyancy in accordance with the water level thereof sothat the valve orifice 98 is opened and closed. The opening of the valveorifice enables the condensate in the valve chest 94 to be dischargedand flows to the outlet port 92 through the outlet passage 99.

FIG. 8 is a sectional view substantially taken along a line A--A in FIG.7, showing a condition that the condensate flows into the valve chest 94from the inlet port 91. As understood from the FIGURE, the sectionalconfiguration of an inlet for condensate which indicates an inletportion, and a portion for connecting the inlet port to the valve chestis generally designed to be circular because of the connection to a pipearrangement. When the condensate flows in this portion, therefore, thecondensate flow is gathered at a portion close to a central portion ofthe inlet port, as shown in the FIGURE, then, becomes a thin water flowand flows down to the valve chest.

In the free float steam trap as mentioned above, the float valve isarranged in a free state in the valve chest, so that there originallyarises such a defect that the float valve is liable to be vibrated.Therefore, when the condensate flow falls in a concentrated manner, asmentioned above, the float valve arranged at the destination of a fallof the condensate flow is significantly vibrated due to the action ofthe condensate flow. As a result, the contact between the float valveand the valve orifice is deteriorated, so that the leakage of fluid,especially, steam in the valve chest occurs.

When the condensate flows into the valve chest 94 from the inlet port 91in a state as shown by an arrow X in FIG. 7, the condensate so exerts asto press the float valve 95 to the valve orifice 98, so that the floatvalve 95 is prevented from opening. As a result, there arises a problemthat the discharge flow rate of the condensate is decreased.

On the other hand, when the condensate concentrically falls on the valveorifice side, the fluid in the vicinity of the valve orifice is broughtinto a turbulent state. Therefore, there arises such a problem thatsteam is liable to be involved in the fluid flowing out to the outletport through the valve orifice.

Further, when the condensate falling in a concentrated manner is evenslightly deflected from the center line of the float valve, namely, theaxis of the valve orifice, the condensate flow so actuates as to pushthe float valve sideward. Consequently, the float valve is turned awayfrom the valve orifice and the leakage of the fluid, especially, steamis induced.

SUMMARY OF THE INVENTION

Accordingly, a technical object of the present invention resides in thatfloat valve is hardly affected by flowing condensate in a free floatsteam trap.

an object of the present invention is to weaken the impact force ofcondensate falling on a valve chest which is exerted on a float valve,whereby the vibration of the float valve is suppressed so that a sealingproperty between the float valve and a valve seat (valve orifice) isimproved and the leakage of steam is prevented.

Another object of the present invention is to restrict the turbulentstate of fluid present in the vicinity of the valve orifice so that theinvolving of steam in the outflow fluid can be prevented.

In order to achieve these objects, the subject matter of the presentinvention resides in a free float steam trap comprising a trap casinghaving an inlet port and an outlet port and provided with a valve chestformed in an interior portion thereof, a valve seat member attached atthe lower portion of the valve chest and having a valve orifice openedthrough which the valve chest communicates with the outlet port, a floatvalve arranged in a free state, rising or descending in positions of thevalve chest in accordance with water level therein to directly open andclose the valve orifice and a means for dispersing and droppingcondensate flow which is provided at an inlet for condensate forconnecting the inlet port to the valve chest.

According to the present invention, the condensate entering the valvechest from the inlet port is dispersed and falls by means of adispersing means. The impact force of the condensate imposed on thefloat valve is, therefore, dispersed, so that the vibration of the floatvalve is controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will be apparentfrom the following description taken in connection with the accompanyingdrawings, wherein:

FIG. 1 is an end view of a free float steam trap showing an embodimentof the present invention;

FIG. 2 is a composite view of an end view taken along a line B--B inFIG. 1 and a sectional view substantially taken along a line C--C inFIG. 1;

FIG. 3 is an end view of a free float steam trap showing anotherembodiment of the present invention;

FIG. 4 is a sectional view substantially taken along a line D--D in FIG.3;

FIG. 5 is a sectional view showing another form of a dam in FIG. 4;

FIG. 6 is an end view taken along a line E--E in FIG. 3;

FIG. 7 is an end view of a well-known free float steam trap and

FIG. 8 is a sectional view taken along a line A--A in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference topreferred embodiments shown in the drawings.

As illustrated in FIG. 1, a cover 14 is fixed to a main body 10 havingan inlet port 11 and an outlet port 12 at upper portions thereof througha gasket 13 by means of bolts 15 so that a trap casing is formed. Avalve chest 16 is formed in an interior portion of the trap casing. Afluid inlet 19 through which the inlet port 11 communicates with thevalve chest 16 is located in a space above a valve seat member 17mentioned below. A cylindrical dispersing screen 18 is so arranged inthe fluid inlet 19 as to direct its axis toward a vertical direction.

The lower end portion of the dispersing screen 18 is closed by an endmember 33. This lower end portion is engaged on a protruding portion 34in the valve chest. A dispersing screen holder 21 is so threaded on themain body 10 from above as to secure the entire body of the dispersingscreen 18. This dispersing screen 18 is divided into an inlet port sideand a valve chest side by a partition wall 22. At the inlet port side isopened an opening portion 23.

On a lower side face of the valve chest 16 is attached the valve seatmember 17 from the inside of the valve chest 16 by means of a threadedmember. In the valve seat member 17, a valve orifice 25 is formed sothat the valve chest 16 communicates with the outlet port 12 through anoutlet passage 24. The valve orifice 25 is so designed as to make itsaxis greater as it goes to the outflow direction of condensate.Therefore, the passing resistance of fluid is adapted to decrease.

On the lower portion of the outlet passage 24, a plug 26 is threaded,from the outside of the main body, to a portion with which thecondensate flow flowing out of the valve orifice 25 collides. The plug26, especially a plane portion with which the condensate flow collidesis made of a material harder than that of the main body 10 so that itcan bear the corrosive action of the condensate flow which flows andcollides therewith at high speed out of the valve orifice 25. The planeportion 27 is so arranged that the condensate flow flowing out of thevalve orifice 25 advances on a substantially central portion of theoutlet passage 24 after it collides with the plane portion 27. In otherwords, the plane portion 27 is so arranged that angles α, β respectivelyformed by the central axis 39 of the valve orifice 25, and thesubstantially central axis 40 of the outlet passage 24 extending to thethicker portion of wall thickness at an upper portion of the main body10, relative to the plane portion 27 are equal to each other.

In the valve chest 16 is accommodated a hollow and spherical float 30made of thin stainless steel plate in a free state. The float 30 floatson the condensate staying in the valve chest 16, rises and descends dueto buoyancy in accordance with a liquid level.

On the bottom face of the valve chest 16, two float seats 31, 32 are soformed as to be substantially parallel with the central axis of thevalve orifice 25. They serve to support and guide the float valve 30 tothe valve orifice 25 when closing the valve orifice. Consequently, whenthe float valve 30 descends as the condensate in the valve chest 16decreases to close the valve orifice 25, the float valve 30 abuts on thethree points 31', 32', 17' of the float seats 31, 32 and the tip end ofthe valve seat member 17 (see FIG. 2), so that a complete sealed stateis realized.

The condensate flowing out of the inlet port 11 enters the inside spaceof the dispersing screen 18 from the opening portion 23 of thedispersing screen 18 and descends. The condensate passing through manypores of the valve chest side, is dispersed and falls in the valve chest16, while foreign materials such as dirt are removed therein. In thecase where the dispersing screen 18 is cleaned, the cleaning can bereadily done through removing the dispersing screen holder 31.

Reference numeral 36 designates a bimetal strip and is formed in asubstantial U-shape in section. This bimetal strip is affixed to themain body 10 through machine screws 37. At the low temperature, thebimetal strip 36 causes the float valve 30 to be separated from thevalve seat member 17 to open the valve orifice 25. At the hightemperature, the bimetal strip 36 is caused to be retracted to a stateas shown in FIG. 2, so that it is disengaged from the float valve 30.

The above-mentioned free float steam trap according to the presentinvention operates as follows.

The condensate entering from the inlet port 11 connected to a portion inwhich the condensate is produced, such as a steam employing equipmentflows into the dispersing screen 18 from the opening portion 23 andfalls in the dispersing screen 18. Since the end member 33 is attachedto the lower end portion of the dispersing screen 18, the condensatedoes not flow into the space of the valve chest 16 which is just underthe dispersing screen 18. The condensate is rectified and dispersedthrough the function of the mesh of the dispersing screen 18 and flowsinto the valve chest 16 from the lower side face of the dispersingscreen 18 as indicated by arrows in FIG. 2.

As a result, the impact force of the condensate imposed on the floatvalve 30 is weakened, so that the vibration of the float valve 30 isrestricted.

Further, since the condensate does not flow to a portion close to thevalve orifice in a concentrated manner, the occurrence of the turbulentflow of the fluid in the vicinity of the valve orifice is restricted.Therefore, steam is hard to be involved in the outflow fluid.

Furthermore, since the dispersed and falling condensate strikes thesurface of the valve float 30 which is closer to the valve orifice 25than a perpendicular passing through the center of the float valve 30,as shown by an arrow in FIG. 1, it does not press the float valve 30 tothe valve orifice 25. Accordingly, the interference of the valve openingoperation of the float valve 30 can be avoided, as a result of which,the condensate can be smoothly discharged.

Generally, in the free float stream trap, the opening degree of thevalve orifice 25 is adjusted depending on the rise and descent of thefloat valve 30, in accordance with the water level of the condensatestaying in the valve chest 16, namely, the inflow rate of condensate, sothat a continuous discharging operation of condensate is effected. Inthe free float steam trap according to the present invention, when thewater level descends in accordance with the discharge of condensate andthe float valve 30 descends and the valve orifice 25 is closed to stopthe outflow of the condensate, the valve orifice 25 can be completelyclosed, because the two lines of float seats 31, 32 are formed inparallel with the central axis 39 of the valve orifice 25.

When the float valve 30 rises due to buoyancy to open the valve orifice25, the condensate flow flowing at high speed out of the valve orifice25 with the plane portion 27 of the plug 26. Then, the direction of theflow is so changed as to extend along the substantially central axis 40of the outlet passage 24. The flow moves upward in the passage 24 andtoward the outlet port 12. The high speed condensate flow, after passingthrough such an outflow path, collides with the thicker portion of awall thickness in the outlet passage 24, so that the influence of thecorrosive action of condensate affected on the life of the steam trapcan be suppressed.

A steam trap shown in FIG. 3 represents another embodiment of thepresent invention. A cover 54 is fixed to a main body 50 having an inletport 51 at an upper portion and an outlet port 52 at a lower portionthrough a gasket 53 by means of bolts to form a trap casing. A valvechest 56 is formed in an interior portion thereof. The inlet port 51 andthe outlet port 52 are horizontally opened and respectively providedwith internally threaded portions for pipe arrangements. A fluid inlet59 through which the inlet port 51 communicates with the valve chest 56is located in a space above a valve seat member 57 mentioned below. Inthe fluid inlet 59 is formed an overall width dam 58 which is slightlyinclined toward the valve chest side. The height of the dam 58 isapproximately half of the diameter of the inlet port 51 or the fluidinlet 59. The inclination of the dam is preferably about 5° to 15° withrespect to a vertical line, however, it may not be limited thereto.

Similarly to the embodiment shown in FIG. 1, the valve seat member 57having a valve orifice 65 is affixed to the lower side face of the valvechest 56 by means of threaded members. A hollow and spherical float 70is accommodated in a free state in the valve chest 56. On the bottomface of the valve chest 56, two float seats 71, 72 are so formed as tobe substantially parallel with the central axis of the valve orifice 65.As a result, when the float valve 70 descends as condensate and thevalve chest 56 decreases to close the valve orifice 65, the float valve70 abuts on the three points 71', 72', 57' (See FIG. 6) of the floatseats 71, 72 and the tip end of the valve seat member 57, so that acompletely sealed state is achieved.

The condensate flowing out of the inlet port 51 is stopped by theoverall width dam 58 until it reaches the height thereof. When theamount of the condensate reaches such an amount as to exceed the heightof the dam, the condensate crosses the dam 58, is dispersed and flowsinto the valve chest 56. In order to improve the dispersing effect forthe condensate, many slits may be provided at the upper edge portion ofa dam 60, as shown in FIG. 5.

Reference numeral 76 designates a bimetal strip similarly to FIG. 1.

The above-mentioned free float steam trap according to the presentinvention operates as follows.

The condensate entering from the inlet port 51 is stored to the heightof the overwall width dam 58. The condensate further entering, therefromcrosses the dam 58, is dispersed and flows into the valve chest 56, asshown in FIG. 4.

As a result, the impact force of the condensate imposed on the floatvalve 70 is weakened, so that the vibration of the float valve 70 isrestricted.

Since the condensate does not flow down to a portion close to the valveorifice in a concentrated manner, the turbulent flow of the fluid in thevicinity of the valve orifice is restricted. Therefore, steam is hard tobe involved in the outflow fluid.

Further, since the dispersed and flowing condensate strikes the surfaceof the float valve 70 which is closer to the valve orifice 65 side thana perpendicular passing through the center of the float valve 70 in thedrawings, the condensate does not press the float valve to the valveorifice 65. Therefore, the interference of the valve opening operationof the float valve 70 can be avoided, and accordingly, the condensatecan be smoothly discharged.

Although the invention has been described in conjunction with specificembodiments, it is evident that many alternatives and variations will beapparent to those skilled in the art in light of the foregoingdescription. Accordingly, the invention is intended to embrace all ofthe alternatives and variations that fall within the spirit and scope ofthe appended claims.

What is claimed is:
 1. A free float stream trap comprising:a trap casinghaving an inlet port and an outlet port and a valve chest formedtherein; a valve seat member attached to the lower portion of the valvechest and having a valve orifice opening through which the valve chestcommunicates with the outlet port; a float valve arranged in a freestate in the valve chest, rising and descending in accordance with thewater level in the valve chest to directly open and close the valveorifice; and a means for dispersing and passing condensate flow downwardhaving an upwardly directed end wall spaced from an upper inner surfaceof the trap casing to form a reservoir, wherein the dispersing means isan overall width dam located substantially above the valve orificeprovided in a fluid inlet through which the inlet port communicates withthe valve chest.
 2. A steam trap according to claim 1 wherein two floatseats are so formed on the bottom face of said valve chest as to beparallel with the central axis of said valve orifice.
 3. A steam trapaccording to claim 1 wherein the overall width dam has manyirregularities on the upper end portion thereof.
 4. A steam trapaccording to claim 3 wherein two float seats are so formed on the bottomface of said valve chest as to be parallel with the central axis of saidvalve orifice.